The present invention relates generally to circuit boards and in particular the present invention relates to circuit boards and methods for improving solder mounting.
Electronic manufacturers use printed circuit boards to electrically connect integrated circuits, and other electrical components such as capacitors and resistors. Population densities of printed circuit boards have increased with the complexity of circuitry and the reduction in size of components. For example, computer motherboards can include hundreds of components including various integrated circuits and surface mount components.
As printed circuit board designs have increased in complexity, the need for additional interconnect lines between the components coupled to the printed circuit boards have increased. To address this need, manufactures have provided multiple layer printed circuit boards where several layers of conductors are separated by layers of dielectric material. These multiple layer circuit boards are fabricated such that the intermediate conductor layers provide power and ground planes to the printed circuit board. The outer layers of the printed circuit board, therefore, are patterned to provide the interconnects and mounting pads for components which are ultimately coupled to the printed circuit board.
The conductive layers of the multiple layer printed circuit boards are connected to each other using vias which are plated with conductive material to provide plated through holes. The vias are located across the printed circuit board and connected to mounting locations on the outer conductive planes using conductive traces. That is, mounting pads for integrated circuits and surface mount components are not directly connected to plated through holes, but are connected to the plated through hole locations using a patterned conductive trace.
For the reasons stated above, and for other reasons stated below which will become apparent to those skilled in the art upon reading and understanding the present specification, there is a need in the art for a circuit board mounting pad which does not include patterned conductive traces.
In one embodiment a circuit board comprises an electrical interconnect mounting pad located on a first surface of the circuit board, and a plated through hole traversing through the circuit board and the electrical interconnect mounting pad. The plated through hole has a first end located adjacent to the first surface of the circuit board and a second opposite end. The second end of the plated through hole is closed such that a liquid material cannot flow through the plated through hole from the first end and out the second end.